Embodiments of the present invention relate to a coupling guard for a rotating member of a turbomachine.
It is well known to apply an air or nitrogen venting to a coupling guard in order to avoid oil migration into the coupling guard. One of these systems is for example described in U.S. Pat. No. 6,474,934.
However, known venting systems are not in general successful to guarantee the right flow to keep coupling guard skin temperature below acceptable values and in addition to avoid oil migration from shaft ends. Such problems are typically solved by increasing the coupling guard overall dimensions and by adding oil guards, for example including seals at the shaft ends. Such solutions have been however demonstrated to be a trial and error approach, which in some cases are not able to keep the skin temperature below 150° C. and not able to stop successfully the oil migration. Further geometrical constraints do not always allow to modify the overall dimensions of the coupling guards or to add oil guards.
It is therefore desirable to modify known venting systems in order to achieve acceptable temperature of the coupling guard skin, at the same time avoiding oil migration from shaft ends and without modifying the overall dimension of the coupling guards or adding oil guards.